The proud King of the land of Cluse in Der Stricker’s Daniel von dem blühenden Tal.
With two invincible giants as his henchmen, he demanded Arthur’s subjugation. Arthur pretended to acquiesce, but only long enough to get his army inside Cluse. Arthur killed Matur in single combat and, with Daniel’s considerable help, proceeded to conquer Cluse. Matur’s widow, Danise, married Daniel.
G. Rosenhagen suggests that his name was meant to mirror Artûs (Middle High German ‘Arthur’), while S. Singer proposes a derivation from the Latin Maturus.
Source
Daniel von dem blühenden Tal | Der Stricker, 1210-1225